A control device of a vehicle power transmission device is well known that includes an automatic transmission shifted by engagement and release of hydraulic friction engagement devices (hereinafter, engagement devices) to selectively establish a plurality of gear stages and an electric motor coupled to an input shaft of the automatic transmission in a power transmittable manner so that a clutch-to-clutch shift is executed while performing regeneration through the electric motor at the time of a coast down shift of the automatic transmission. For example, this corresponds to a control device of a vehicle drive device described in Patent Document 1.
During clutch-to-clutch shift of the automatic transmission associated with regeneration through the electric motor, it is conceivable that, for example, a regenerative torque from the electric motor, i.e., an electric motor torque (transmission input torque) is varied in accordance with a change in rotation of the electric motor during an inertia phase to perform an equal power shift not changing regenerative power (=regenerative torque×electric motor rotation speed) (see broken lines of FIG. 8). However, since an engagement-side engagement device starts having a torque capacity to change a gear ratio to a post-shift gear ratio in a torque phase during the clutch-to-clutch shift before a change in rotation of the electric motor in the inertia phase and an inertia torque is generated in the inertia phase, if the equal power shift is performed, a drop-off D is generated in torque on the output side of the automatic transmission (e.g., transmission output torque) in the torque phase and the inertia phase (see broken lines of FIG. 8). Since it is concerned that such a drop-off D of the transmission output torque is made larger when the clutch-to-clutch shift is executed while the regenerative torque is larger, a proposal has been made to provide regenerative torque reduction control of temporarily reducing the regenerative torque in the torque phase and the inertia phase (see solid lines of FIG. 8). For example, torque-phase compensation control reducing the regenerative torque is provided during the torque phase to compensate the drop-off D of the transmission output torque in the torque phase (see A of FIG. 8), and inertia-phase compensation control reducing the regenerative torque is provided during the inertia phase to cancel the inertia torque (see B of FIG. 8). These compensation controls suppress the drop-off D of the transmission output torque (see C of FIG. 8).
On the other hand, in the clutch-to-clutch shift of the automatic transmission, it is desired to suppress a shift shock while properly ensuring shift responsiveness. Therefore, for example, an oil pressure command value is set in consideration of the shift shock suppression, the shift responsiveness, etc., in hydraulic control of the engagement devices in the clutch-to-clutch shift. However, a shift shock may unexpectedly be increased due to temporal change etc., of hydraulic control components (e.g., components such as friction materials (friction plates) making up the engagement devices, clutch plates, pistons, and return springs) of the automatic transmission and operating oil. Therefore, a proposal has also been made to provide oil pressure learning control of sequentially detecting a degree of change in transmission input rotation speed during the clutch-to-clutch shift to set the next oil pressure command value in the direction suppressing the shift shock. For example, the learning control of a release oil pressure of a release-side engagement device is provided such that an undershoot amount of the transmission input rotation speed converges to a target before the inertia phase, and the learning control of an engagement oil pressure of the engagement-side engagement device is provided such that a change rate of the transmission input rotation speed converges to a target during the inertia phase.